High-voltage electric circuit breaker

ABSTRACT

A high-voltage electric circuit breaker has two mutually oppositely movable contacts which cooperate with two stationary contacts, the movable and stationary contacts being positioned on a common axis, and the two movable contacts being actuated by two bell-cranks which translate transverse motion from an actuator to motion in alignment with the movable contacts to open and close the latter relative to the stationary contacts. The two bellcranks are pivoted on the same axis but are laterally offset from each other so that they can swing free from each other by overlapping each other. This permits the bell-cranks to have a large lever ratio but by swinging in overlapping axes, to be enclosed in a relatively small casing. Thus it is possible to move the movable contacts through longer strokes and permit them to be of the piston and cylinder arc-blasting type.

Noack et a1.

[5 HIGH-VOLTAGE ELECTRIC CIRCUIT BREAKER [75] Inventors: Dieter Noack; Heiner Marin, both of I Berlin, Germany [73] Assignee: Siemens Aktiengesellschaft, Munich,

Germany [22] Filed: Jan. 15, 1973 [21] Appl. No.: 323,720

[30] Foreign Application Priority Data Jan. 28, 1972 Germany 2204556 [52] U.S. Cl 200/148 F, 200/145 [51] Int. Cl. H01h 9/40 [58] Field of Search 200/153 H, 148 R, l48 F,

ZOO/153 G, 18, 145; 335/189, 191; 74/519 [56] References Cited UNITED STATES PATENTS 1,920,894 8/1933 Ruppel ZOO/148 F 2,981,814 4/1961 Friedrich 200/145 X 3,071,671 1/1963 Leeds 200/145 X 3,740,506 6/1973 Yoshioka et a1, 200/148 F X n11 3,324,361 [451 July 16, '1974 Primary Examiner-Robert K. Schaefer Assistant Examiner-William J. Smith Attorney, Agent, or Firm-Kenyon & Kenyon Reilly Carr & Chapin [5 7 ABSTRACT A high-voltage electric circuit breaker has two mutually oppositely movable contacts which cooperate with two stationary contacts, the movable and stationary contacts being positioned on a common axis, and the two movable contacts being actuated by two bellcranks which translate transverse motion from an actuator to motion in alignment with the movable contacts to open and close the latter relative to the stationary contacts. The two bell-cranks are pivoted on the same axis but are laterally offset from each other so that they can swing free from each other by overlapping eachother. This permits the bell-cranks to have a large lever ratio but by swinging in overlapping axes, to be enclosed in a relatively small casing. Thus it is possible to move the movable contacts through longer strokes and permit them to be of the piston and cylinder arc-blasting type.

3 Claims, 3 Drawing Figures l HIGH-VOLTAGE ELECTRIC CIRCUIT BREAKER BACKGROUND OF THE INVENTION Certain high-voltage circuit breakers operate by simultaneously moving two movable contacts which cooperate with stationary contacts, the contact sets being electrically connected in series. For circuit breaking, the two movable contacts are pulled towards each other away from the fixed contacts, all of the contacts being positioned on substantially the same common axis or center line with the movable contacts between the stationary contacts.

Such a construction presents the problem of simultaneously pulling the two movable contacts in opposite directions away from the fixed contacts with the best possible contact-motion increasing lever-advantage during circuit breaking operation. If the movable contact strokes can be made long enough, the use of piston and cylinder arc-blasting contacts is made possible.

To effect good electrical insulation between the electrically powered components and the grounded metal enclosure within which these components are spaced, it is customary to use a compressed gas insulation, such as compressed SF In other types of constructions the movable contact of a circuit breaker can include a piston and cylinder arrangement which during circuit breaking forms a blast of the compressed gas insulation to extinguish any are that forms between the separating contacts. But in case of constructions of the type described using the two in-line sets of movable and fixed contacts in electrical series, the levers or bell-cranks required to operate the two movable contacts simultaneously, because of space restrictions has not heretofore provided asufficient motion-increasing lever advantage to permit the movable contact operating mechanism to provide the greater range of motion required by such arc-blasting contacts.

SUMMARY or THE INVENTION One of the objects of the present invention is to provide a construction wherein a high-voltage circuit breaker of the type having such two sets of contacts may be simultaneously actuated through bell-cranks, by a transversely moving actuator, with a sufficient motion to permit the movable contacts to be of the arcblasting type.

According to the present invention, this object isattained by arranging the two bell-cranks, or two-armed levers, so that they are rotatively mounted on the same axis but are axially offset or positioned side by side to swing passed each other with overlapping motions. With this arrangement a transverse actuating motion relative to the contact alignment, permits the two bellcranks to operate without interference with each other, thereby permitting longer swings imparting a longer stroke to each of the movable contacts and thus permitting these contacts to be made in the form of arcblasting types.

BRIEF DESCRIPTION OF THE DRAWINGS A specific embodiment of the present invention is illustrated by the accompanying drawings in which:

FIG. 1 is a partly vertically-sectioned elevation of a high-voltage circuit breaker of the multiple contact, series-connected type referred to and incorporating the principles of the present invention;

FIG. 2 is a partly sectioned elevation of one of the bell-crank or lever elements; and

FIG. 3 is a cross section taken on the line 3-3 in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, the high-voltage circuit breaker shown is of the metal-clad type having a grounded metal housing or casing 1 filled with a suitswitching device includes a stationary contact 13 and t a movable contact 14 reciprocating in a member 15 which is tubular and serves as a nozzle for an arcblasting jet of the compressed insulating gas and also to carry current from the contact 14. When the electrodes 13 and 14 are closed together, a closed circuit is formed via the electrode 13, the contact 14, to the member 15, and so to a stationary metal housing 16 which is positioned in the casing part 2 between the two switching devices 11 and 12 and connects these devices electrically in series. This metal housing 16 is positioned by a hollow insulator 20 rigidly connected to the housing 16 at one end, the other end of this insulator 20 which extends into the stub 4 being rigidly connected to a cover 21 which is part of the housing of a circuit breaker actuator 22.

p In the assembly under description the circuit breaker actuator is a double-acting hydraulic actuator. It provides, via a bell-crank 22a, a reciprocating motion longitudinally with respect to the tubular insulator 20, through a connecting rod 24, which is also electrically insulating, and which is guided in the metal housing 16 by way of a bearing 25.

With reciprocative motion of this connecting rod 24 counter-rotative two-arm levers 26 and 27 are swung by way of two toggle arms 28 and 29, the longer arms 26a and 27a of the two levers through connecting rods 30 being coupled with the movable contacts 14 of the two switching devices 11 and 12.

In addition, the actuating or connecting rods 30 are connected in each instance with a blast cylinder 31 which during contact opening operation is pulled over a stationary blast piston 32 so that the compressed insulating gas is further compressed and blasted through the nozzles 15 to blow out any arc that forms.

The space within the metal housing 16 is limited but In other words, the lever arms shown at 27b in FIGS. 2 and 3, connected by the toggles 28 and 29 to the reciprocative rod 24, may be shorter relative to the arms 26a and 27a so that the connecting rods 30 may be moved much greater distances than have heretofore been possible. This effect is obtained because the two levers 26 and 27 are mounted on the same axis symmetrically with respect to each other and are axially offset so that they can move relative to each other without any mutual interference.

In FIG. 2 one of the bell-cranks or two-arm levers is schematically shown on an enlarged scale, FIG. 3 showing the cross section. This is the lever 27 but both are identical. It has a bearing or journal part 35 which is rotative about the pivot bar 37, shown in FIG. 1, which is common to the two bell-cranks 26 and 27. This part shown by FIGS. 2 and 3 has the one long arm 27a and the shorter lever arm 27b, the longer lever arm 27a being connected through a pivot 36 with the movable contact and cylinder actuating rod 30, while the pivot bearing on the free end of the shorter arm 27b is pivoted to the toggle link 29 actuated by the connecting rod 24.

FIG. 3 shows that the two lever arms 27a and 27b are offset axially with respect to each other, this providing 4 for a further offset axially when this lever 27, shown in FIGS. 2 and 3, is positioned side-by-side with the corresponding bell-crank 26.

What is claimed is:

l. A high-voltage electric circuit breaker having two electrically series-connected axially aligned sets of contacts including movable contacts which are moved by bell-cranks actuated by a common member reciprocative transversely with respect to the alignment of the contact sets, each of the bell cranks having two arms conjointly defining a pivot location where the two arms are joined to each other; wherein the improvement comprises said bell-cranks being pivoted at the pivot locations thereof on a common axis and laterally offset from each other in side-by-side arrangement to avoid mutual interference.

2. The circuit breaker of claim 1 in which said bellcranks have shorter arms mutually swung by said actuator and longer arms connected to said movable contacts.

3. The circuit breaker of claim 2 in which said bellcranks are enclosed by a housing and swing relative to each other in overlapping arcs.

- UNITED STATES PATENT OFFICE CERTIFICATE 9F CORRECTION Patent No. 3,822+,361" Dated July 16, lQjU- InventorKs) Dieter Noack, Heiner Marin It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Foreign Application Priority Data change the file number of the German application upon which the claim for priority is based from "220M556" to 22 on 656.6--

si ned and sealed this 26th day of November 1974.

(SEAL) Attesta McCOY M. GIBSON JR. Attesting Officer 0; MARSHALL DANN Commissioner of Patents FORM F'O-105O (10-69) USCOMM DC 6376 p69 a u.s. GOVERNMENT PRINTING OFFICE: Isis 0-366-334.

- UNITED STATES PATENT OFFICE CERTIFICATE 9F CORRECTION Patent No. 3, 824361" r Dated I July 16 197 Inventor(s) Dieter Noack, Heiner Marin It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Foreign Application Priority Data change the file number of the German application upon which the claim for priority is based from "2204556" to 22 O I- 656.6--

Signed and sealed this 26th day of November 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. Attesting Officer 0; MARSHALL DANN Commissionerof Patents FORM PO-105O (10-69) USCOMM- 0375-p59 4: us. eovzauuzn'r PRINTING onfics: 196s 0-356-334. 

1. A high-voltage electric circuit breaker having two electrically series-connected axially aligned sets of contacts including movable contacts which are moved by bell-cranks actuated by a common member reciprocative transversely with respect to the alignment of the contact sets, each of the bell cranks having two arms conjointly defining a pivot location where the two arms are joined to each other; wherein the improvement comprises said bell-cranks being pivoted at the pivot locations thereof on a common axis and laterally offset from each other in side-by-side arrangement to avoid mutual interference.
 2. The circuit breaker of claim 1 in which said bell-cranks have shorter arms mutually swung by said actuator and longer arms connected to said movable contacts.
 3. The circuit breaker of claim 2 in which said bell-cranks are enclosed by a housing and swing relative to each other in overlapping arcs. 